This invention relates to a printed circuit board assembly with improved heat sinking.
It is often necessary to dissipate heat from electronic components which are mounted on printed circuit boards (PCB). Conventionally, this has been accomplished by providing a heat sink between the electronic component and the PCB. This has also been accomplished by providing a heat sink directly on top of the electronic component. However, such assemblies are expensive to manufacture.
It is known to enclose or xe2x80x9cpackagexe2x80x9d relatively high power surface mount (SMT) components using a package style known as xe2x80x9cD-squared packagexe2x80x9d (DDPAK), wherein a component""s package is basically the outside plastic enclosure and leads. The electronics industry refers to such an assembly as a package, because the actual silicon is inside the enclosure. If a circuit assembly includes multiple DDPAK SMT components, then the normal DDPAK xe2x80x9cfootprintsxe2x80x9d may not provide sufficient heat transfer away from the components. This problem is aggravated when the circuit board is enclosed in a plastic case rather than metal enclosure. Accordingly, a heat sinking assembly which overcomes these problems is desired.
Accordingly, an object of this invention is to provide an efficient heat sink arrangement for surface mounted electronic components.
This and other objects are achieved by the present invention, wherein a circuit assembly includes a printed circuit board with metallic traces formed thereon, and heat generating electronic components surface mounted on the board in contact with a part of the traces. A heat conducting metal plate is mounted on the board adjacent to and spaced apart from the electronic component. The plate contacts a second part of the traces. A heat conducting, electrically insulating pad is mounted on the plate, and a heat sink member is mounted on the pad so that the pad is between the heat sink member and the traces. A heat conducting metallic (solder) bridge is formed between an edge of the electronic component and an edge of the plate.